Protecting device for circuit breakers



Dec. 22, 1953 A. VlBOUD ET AL 2,663,779

PROTECTING DEVICE FOR CIRCUIT BREAKERS Filed May 15, 1952 5 Sheets-Sheet 1 Fig.1

5 .36 44 43 Invemors Alberi' VIBOUD An r ems Arwrne;

Dec. 22, 1953 A. VIBOUD ET AL 2,663,779

PROTECTING DEVICE FOR CIRCUIT BREAKERS Filed May .15, 1952 5 Sheets-Sheet 2 I nv e n "r or s Albert VIBOUD Andre GR/QS' a B y Mg/iwiuk A Home Dec. 22, 1953 A. ViBOUD ET AL I 2,663,779

PROTECTING DEVICE FOR CIRCUIT BREAKERS Filed May 15, 1952 5 Sheets-Sheet 3 Fig 6 13 l 53 7 l r-------------- fi I"- FIIIZ1- I:' :EI I: ZZJ I w i :i: 3 l lnven'lors tI I Albert VIBOUD L l Andr GRAS 1:113:11- -J, Y By K M W Attorney Dec. 22, 1953 A. VIBOUD ETAL 2,663,779

PROTECTING DEVICE FOR CIRCUIT BREAKERS Filed Ma: 15 1952 5 Sheets-Sheet 4 Inventor:

Alber? VlBOUD Andre GRAS 5, AMA mm AHornay Dec. 22, 1953 A. VIBOUD ETAL 2,663,779

PROTECTING DEVICE FOR CIRCUIT BREAKERS Filed May 15, 1952 5 Sheets-SheetS Inventors A-lbert VIBOUD Andra GRAS AHorney Patented Dec. 22, 1953 UNITED STATES ?ATENT OFFICE PROTECTING DEVICE FOR CIRCUIT BREAKERS Albert Viboud and Andr Gras, Grenoble, France, assignors to Etabiissements Merlin & Gerin, Societe Anonyme, Grenoble, France, a corporation of France 12 Claims.

The invention is concerned with a device for protecting circuit breakers against unintentional closing of the contacts. Such unintentional closing may for instance occur when the circuit breaker or switch of any type, with at least one fixed or stationary contact and at least one movable contact, is employed in any switching apparatus, switch box, on a switch board, panel, or the like of a mobile station on any vehicle, ship, railroad, aircraft, or any other mobile conveyance which during its locomotion is exposed to vibrations or sudden shocks, such as from change of direction or speed r other causes.

If in the following specification and in the claims switch elements are designated as stationary, the term stationary is to be understood to relate to those parts which are fixed or per manently at rest at the switching apparatus and in the mobile vehicle which parts, however, of course move together with, but not relatively to, the mobile vehicle.

The contacts, opposite to, and cooperating with a.

the stationary contact are the movable contacts. such as blades, knives, brush contacts, face contacts, or the like. The invention particularly relates to such movable contacts carried on a shaft through the turning of which the contacts are closed and opened. These contacts carried on a shaft may be the movable main contacts or the movable contact of a circuit breaker or switch or they may be auxiliary contacts, or an auxiliary contact, such as conventional in the art or convenient for preventing the formation of the are, or arcing the arc, or extinguishing or blowing out the arc.

The invention is concerned primarily with the actuating means of the movable contact or contacts in circuit breakers or switches of the aforesaid type and a primary object of the invention is a development of such actuating means which prevents the movable equipment or mechanism of the circuit breaker from, or protect it against, being moved unintentionally to such an extent that the movable contacts or contact might engage the stationary contacts or contact. Such unintentional engagement might occur when, during or through the operation of the vehicle or the like, vibrations or shocks are produced of an intensity sufficient to cause movement of the movable mechanism or equipment through its inertia relatively to the stationr contacts to an extent that the movable m contacts or arcing or other auxiliary contacts or contact engage, even if only transitorily, the stationary contacts or contact and the current is switched on, if even to be interrupted immediately thereafter.

It is thus an object of the invention to provide the actuating means of the movable equipment of the circuit breaker or switch with an impeding mechanism which, on the one hand, impedes or makes impossible the making of the contact on unintentional movement of the movable parts or equipment of the switch whereas by intentional movement of this equipment the impeding mechanism may be inactivated and the circuit breaker or switch at wish closed or opened, the great risks involved with an accidental closing of the contacts thus being avoided.

A further object of the invention is to apply this inpeding mechanism to the actuating shaft of the movable equipment in such a manner that the mechanism is unidirectionally operative or eiiective, i. e., that the impeding mechanism distinguishes between movements in the opening sense and movements in the closing sense so as to allow the circuit breaker or switch to be opened unimpededly.

It is furthermore an object of the invention to render the impeding mechanism selective, so that it may select between movements of the movable equipment relatively to the stationary equipment of the switch when, on the one hand, through shock or vibration, the switch as a whole executes a coerced movement and through the inertia of the movable equipment a turning movement is produced at the shaft which would tend to close the switch and, on the other hand, when through intentional actuation of the actuating means, turning moments are produced at the shaft which tend to close or to open the circuit breaker. In the one case the impeding mechanism is to impede movement of the shaft, in the other case it is to release such movement.

The protecting device for circuit breakers with p at least one contact pair having a stationary and a movable contact, a shaft carrying the movable contact, and actuating means for closing and opening the contacts, in accordance with the invention thus includes a unidirectionally selective impeding mechanism associated with the shaft.

This impeding mechanism is adapted for taking up turning moments caused, on coerced movement of the circuit breaker as a whole, through inertia of the movable contact and produced by, and arriving at the impeding mechanism from, movement of the movable contact relatively to the stationary contact and in the closing sense, unintentional closing of the contacts thus being avoided. The impeding mechanism is further adapted to release the shaft for movement by turning moments produced at the shaft by intentional actuation of the actuating means for operation of the circuit breaker in either sense, opening and closing the contacts.

The impeding mechanism may be of various types. The mechanism may thus be unidirectionally'responsive to angular displacement of the shaft in the closing sense. The mechanism will thus be unresponsive to movements of the shaft in the opening sense but Will respond to angular displacement of the shaft in the closing sense and selectively will resist such movement during a first certain angle of this movement in the closing sense while it will release its resistance when the shaft has been moved above this angle. In this way unintentional closing of the contacts is prevented when the movable contact through its inertia moves out of its open position. The contacts however may be intentionally closed when, by means of the actuating means, the shaft is moved through and above this angle.

In an embodiment of this development of the invention, the mechanism which resists the unintentional closing of the contacts includes a sta tionary member, that is, stationary relatively to the stationary part or equipment of the circuit breaker, further includes a movable member disposed on the shaft and interengaging means which are unidirectionally responsive to angular displacement of the shaft in the closing sense.

This resisting mechanism may include a brake r mechanism with means which, during a first certain angle of displacement of the shaft relatively to the stationary parts of the circuit breaker, cause the brake members to engage each other and thus to brake and impede the movement of the shaft. These means, when through intentional operation of the shaft the resistance of the brake mechanism has been overcome and the shaft has moved through and above this angle, will then release the brake members from engagement and allow the shaft to be freely moved by the actuating means for closing the contacts.

By these means, the resisting mechanism may be so designed that the energy of even the greatest shock as might occur and act upon the movable equipment of the circuit breaker in the sense of closing the contacts is absorbed through the frictional moment before the fixed and movable main contacts or arcing contacts might touch each other. On the other hand, the action of the frictional moment ceases as soon as by intentional operation of the actuating means the angular displacement has reached a certain predetermined value and the frictional resistance on this path once has been overcome.-

In another development of the invention the impeding device may include a locking mechanism comprising a stationarily mounted locking member and cooperating therewith a stop member mounted on, and secured to, the shaft and engaging the locking member in the "open position of the shaft, i. e. the position of the shaft where the contacts are open. A release member is secured to the actuating means to be actuated thereby for lifting the locking member out of engagement with the stop member when the actuating means are moved in the sense to close the contacts. Coupling means are provided which, on disengagement of the locking mechanism, couple the actuating means and the shaft for closing the contacts by actuation of the actuating means.

Unintentional closing of the contacts out of the open position of the movable contact or equipment is thus prevented how intensive the shocks or vibrations may be, but intentional closing and opening of the contacts is made possible without any hindrance.

In order to more clearly point out these and other features and objects of the invention, reference will now be made to the accompanying drawings which form part of thi specification and which by way of example illustrate various embodiments of our invention. These drawings are to be understood explicative of the invention but not limitative of its scope.

Other embodiments incorporating the principle underlying our invention are feasible without departing from the spirit or ambit of our appended claims.

In the drawings:

Fig. 1 is an elevational front view of a switch with actuating means and protecting device of the invention embodied as a resisting mecha- .ism, and more particularly a brake mechanism;

Fig. 2 is a similar view of the resisting mechanism of Fig. 1 partly in section, taken on line 2-2 of Fig. 4, and on an enlarged scale;

Fig. 3 is an elevational side view taken along line 3-4; of Fig.1;

Fig. 4 is an elevational section, along line 4*"6 of Fig. 1, the brake mechanism being in its disengaged position for a switch in it closed position;

Fig. 5 is the same sectional view, the brake mechanism being in its engaged position for the switch in its open position;

Fig. 6 is an elevational front view of a second embodiment of the invention embodied as a locking mechanism for a switch or circuit breaker for manual operation as well as for operation by remote control;

Fig. 7 is a side view taken along line 7-! of 6 showing diagrammatically the switch or circuit breaker of Fig. 6;

Fig. 8 is a view similar to that of Fig. 6 partly in longitudinal section along line 8-8 of Fig. 9 of the locking device mechanism and on an enlarged scale;

Fig. 9 is a section along line 9---! of Fig. 8;

Figs. 10 to 13 are side views of the manually operated part of the locking mechanism in Various positions;

Fig. 14 is a diagrammatic perspective of the remote control part of the locking mechanism of Figs. 6 and 8;

Figs. 15 and 16 are side views of details of the remote control part of the locking mechanism.

In the embodiment shown in Figs. 1 to 5, a switch or circuit breaker of any type is schematically indicated at H. I2 are the fixed or stationary contacts, I 3 the movable contacts such as in the form of blades, knives, brushes, or the like. The shaft which carries the movable contacts or contact 13 is designated by M.

The shaft l4 may be actuated by any c0nVenient or conventional means, by remote control or, as indicated, by a handgrip I5.

Shaft I 4, handgrip l5, and blades I 3, in this instance, represent the movable equipment of the switch.

In this embodiment the unidirectionally selective impeding mechanism is a resisting mechanism' with a stationary member, a movable member disposed on the shaft to be movable therewith, and with interengaging means responsive to angular displacement of the shaft in the closing sense.

In this instance of Figs. 1 to 5, where the resisting mechanism includes a brake mechanism, the stationary member is the brake casing I 8. The casing is fixed to the switch panel or other stationary structure, not shown, by a rod system including an adjustable rod 48 secured to casing [8 by means of a holding plate riveted to the casing. The brake casing is rotatably carried on shaft M by means of a sleeve 2i with its one end extended into the casing l3 and provided at this end with a flange 25. At the other, the outside end, the sleeve is provided with a screw thread 22. Sleeve 2| furthermore is shaped with two fiattenings 23, 24, at opposite sides, and the casing I8 is correspondingly perforated, so that casing l8 and sleeve 2| are keyed together in the peripheral direction but are displaceable relatively to each other in the axial direction.

An adjusting ring 26 is screwed on the sleeve and adjusted in its position by means of set screw 2! which sets on one of the flattenings, in the instance illustrated, the lower one, 24. Secured to the casing l8, for instance riveted, is a flanged bush 28, between whose flange 29 and the adlusting ring '26 a coil spring 38 is extended which thus urges the sleeve with its flange 22 towards the casing 18.

The movable member of the resisting mechanism is a carrier disc 3! which by means of a pin 32 is secured to shaft 44. Disc 3| carries a number of pawls 35, in the present instance three, evenly distributed over the circumference. The pawls 35 are freely turnable about their pivots 36. Springs 31, likewise attached to the carrier disc 3i, urge the noses of the pawls towards the teeth of a ratchet wheel 38. The ratchet wheel 38 is provided at both its sides with annular discs 33, 40, of any conventional or convenient brake lining material, Together with these discs or brake linings ratchet wheel 38 is circularly perforated so as to be freely revolvable about sleeve 2|.

An annular shoulder disc 4| is likewise keyed by the flattenings 23, 24, against peripheral displacement but axially displaceable on sleeve 2! and is seated between flange and the adjacent annular disc or brake lining 39.

By means of spring 3%] whose tension may be regulated by the setting of adjusting ring 28, the Whole set consisting of di cs 4!, 33, 33, as, is longitudinally compressed between flange 2 of sleeve 2! and the wall of the casing I8. In this brake assembly, shoulder disc 4| and casing it thus comprise the stationary brake member whilst the ratchet wheel 33 with its linings 3Q, comprise the movable brake member. effect will thus be produced between shoulder disc H and easing l8, on the one hand, and the two linings 39, at, on the other hand, as soon as the movable brake member 35, it starts turning relatively to the stationary brake member M, 58.

The movable brake member 39, 33, All, however, is not coupled with the shaft in a unique sense so that it would be coupled in any condit on w th the shaft and the carrier disc 3! of the device thereon when the shaft M with sh. is turned clockwise, Figs. a and 5, or in the sense of arrow F in Fig. 2, the sense in the clrcult breaker is to be closed. The movable br ke member rather forms part of the interengag 1g mechanism which imparts to the impeding or resisting mechanism unidirectional and selective characteristics.

Whereas the pawls ensure potentially to the shaft may be engaged with the brake when the shaft is turned in the closing sense, they ensure A strong braking also that the shaft remains disengaged from the brake mechanism when the shaft is turned in the opposite, the opening sense. The inter-engaging mechanism so far is unidirectional. But it is also selective through the following release mechanism operable through the angular displacement of the shaft.

This release mechanism comprises rollers 32 at the free ends of the pawls which when riding on the inside surface of the cylindrical wall 44 of the casing I8 will lift the pawls 35 out of engagement with the ratchet wheel 32- but when reaching windows 43 provided in wall it will release the pawls 35 to be urged by the springs into engagement with the ratchet wheel 33.

The pawls thus are so disposed at their carrier disc that the roller at the free end of each pawl may either ride on the cylinder wall of the easing and on and during contact with this wall will lift the pawl nose out of engagement with the toothed rim of the ratchet wheel or that the roller on its path will find and enter a window and will thus release the pawl for engagement with the ratchet wheel.

The function of the device is as follows:

The casing I8, 44, with its windows 43 is so a ljusted by means of the adjustable rod it that in the open position of the circuit breaker the rollers 42 of the pawls 35 may enter the windows If in this open position of the circuit breaker a shock or vibrations act upon the movable equipmerit of the switch and move blades l3 and handgrip l5 of the movable equipment, these parts, since they are secured to the shaft, will take the shaft l4 along and tend to turn it in the closing sense, arrow F in Figs. 2 and 4.

The disc 3! which is keyed to shaft it turns together with the shaft. Since the rollers have entered the windows 43, the pawls 35 engage the ratchet wheel 38, and tend to take it along.

The ratchet wheel however offers strong resistance to this movement in View of the great friction which is produced between the linings 40, and the metal discs l4, l8, respectively. energy of the shock will thus be absorbed by friction.

The pressure of spring 30 and the peripheral lengths of the windows are so determined that intensity and duration of friction suince to absorb the greatest shock energy which might occur. It is obvious that the absorption of the shock energy must be accomplished principally by the intensity of the friction and that thewfore a very strong spring 30 is to be applied since the length of time during which the friction is efiec tive corresponds to the angular displacement of disc 3| during which displacement the rollers may move along the windows and, moreover, the displacement itself is to be limited to a certain, relatively narrow angle in order to exclud with certainty any accidental contact between the main contacts or the spring contacts.

When the energy of the shock or of the vibrations has been absorbed, the movable equipment will, unimpeded by the pawl and ratchet inechanism return into its rest or open position.

The frictional moment produced in the brake mechanism is or course to be overcome when the switch or circuit breaker is to be closed tentionally. If the brake mechanism were cc operative over the whole angular displacement of the switch from the "open to the closed position, this would tend to slow down the closing movement, whereas, to the contrary, the movable contacts, at the moment of closing, should have a very great velocity. The invention therefore provides, that after a certain time, or after a certain angle of travel has been completed, the efiect of the frictional moment ceases. This end is achieved by determining and disposing the peripheral lengths of the windows in relation to the uninterrupted peripheral lengths of the cylinder walls, from window to window, so that as soon as the angle corresponding to the peripheral length of a window and provided for the absorption of the shock energy has been traversed, the rollers reach the uninterrupted arc of the cylindrical wall 44, are pressed inwards while continuing their course. The pawls 35 will now be pivoted about their pivots 36 and their noses will thus be lifted out of engagement with the ratchet wheel 38. The ratchet wheel will no longer be turned, the frictional moment vanishes, and the closing movement may be completed without any further hindrance.

The duration of the frictional coupling may be regulated through adjustment of the position of the casing M3 by varying the length of rod i9 and thus changing the position of the rollers 35 in the open position relatively to the edges of the windows 43 and correspondingly the magnitude of the angular displacement during which the frictional moment or couple is effective.

It will readily be appreciated that the device as just described may absorb not only the energy of an accidental shock but also that of oscillations of a certain range. As soon as the undesired or unintentional influences have ceased, the shaft will return under the influence of the gravity of the movable equipment into the normal open position of the circuit breaker or switch and the device is again ready for function.

Figs. 6 to 16 illustrate an embodiment wherein the shaft which carries the movable contacts or contact and the actuating means will be coupled together for actuation and will then be disconnected from one another. In this embodiment the device which protects the switch or circuit breaker against unintentional closing through inertia of the movable equipment and caused by coerced movement of the circuit breaker as a whole, includes a locking mechanism for locking the shaft against unintentional movement.

i I again indicates schematically a switch or circuit breaker of any type with the stationary contact or contacts l2 and the movable contact or contacts l3, carried by the shaft In this embodiment the means for operating the switch manually is the handgrip 52 and the actuating means for remote control are an electromagnet T4 with armature 15, levers 11 and 82, and sleeve 83, as may be seen from Figs. 6, 8, and 9, the details of the members for manual control being shown in Figs. to 13 and those for remote control in Figs. 14 to 16.

The locking mechanism which prevents the switch from being closed unintentionally and which looks the shaft 5| and thus the movable equipment from being moved, until by intentional actuation of the actuating means, manually or by remote control, the locking mechanism is released, comprises a locking member in form of a locking bar 52 pivotally mounted at 54 upon a stationary support 53. Support 53 is secured by any conventional means, not shown, to the panel of the switch or other structure supporting the same. A leaf spring 51 secured to the support urges the locking bar 52 upwards against a stop member in form of a cam 55 mounted upon and secured to shaft 5|. Cam 55 of generally semi-circular contour is shaped with a notch or indentation 56 into which the locking bar 52 will enter when shaft 5| is in the open position of the circuit breaker or switch. Notch or indentation 56 will thus serve as a stop, preventing shaft 5| from being unintentionally moved in the closing sense until, on intentional actuation of the actuating means for closing the switch, proper release mechanism will lift or pivot the locking bar 52 out of engagement with notch or indentation 55 of the stop member or cam 55, and coupling means will thereon couple the actuating means with shaft 5:, as will be described hereinafter.

The release members for the locking bar 52 are two cams 59 and 50 both loosely mounted on shaft 5|. One cam, 59, for manual 0 eration is secured to the handgrip 52, loosely mounted on shaft 5|, the other cam 60, for remote control is secured to sleeve 83 likewise loosely mounted on shaft 5|.

In the rest position of the circuit breaker where both, handgrip 52 and sleeve 55, are uncoupled or disconnected from the shaft and are loosely movable thereon, the cams 59 and 55 through their shapes are disengaged from the locking bar 52. On being pivoted about axis 5|, each cam, independently of the other, will strike against the locking bar 52 and thereby tilt against the tension of spring 51 the locking bar about pivot 54 out of the indentation or notch 55 of stop cam 55.

Handgrip 62 terminates in a fork 53 by means of which it is loosely mounted on shaft 5%. Cam 59 is secured, by soldering, brazing, or welding, for instance, to one branch of the fork.

The branches of fork 53 embrace cam 55 and opposed thereto carry a pawl 55 loosely pivoted at $5. The pawl 55 is so suspended that its center of gravity is below its pivot 55, as shown in the rest position of handgrip 52 is Fig. 9, and where the pawl bears with its tail end against an abutment pin 66 which prevents undesired deflection of the pawl in the one direction.

The upper contour Bl of the pawl is so shaped that in this position, Fig. 9, the pawl just clears the unindented semi-circular contour of cam 55, so that this cam may unimpededly pass the pawl when the cam is turned together with shaft 5| by actuation of the remote control device which will be described in detail later on.

When the switch is to be closed, the handgrip 52 is moved from its rest position, Fig. 9, upwards in the sense of arrow F. The cam 55 will strike against the locking bar 52 and tilt it in the sense of arrow K, Fig. 10, out of engagement with identation 55 of cam 55.

Cam 55 and together with it shaft 5! are thus released for movement or actuation in the closing sense. On further movement of the handgrip 52 and when the handgrip has reached the position of Fig. 10, the arc contour of cam will hold the locking bar disengaged. The upper contour of the pawl will no longer be guided along the contour of cam 55 and no longer be held with its tail end against abutment pin 55, but will by its gravity turn about pivot 55 and snap with a corner notch 58 over edge 58 of cam 55.

By moving the handgrip downwards in a sense opposite that of arrow F into the position shown in Fig. 11, a position of handgrip 62 beyond its normal rest position, the switch is closed. The handgrip may now be released and will thus fall into its loose, rest position 9 where the pawli is disengaged from cam 55'- and likewise takes its loosely suspended rest position, Fig. 12;

When the switch or circuit breaker is to be opened, the handgrip: is lifted again, in the drawing counterclockwise, until the front edge of the fork 83 abuts against a pin l9- providcdin an extension ii at the: top edge of camv 55; On further movement the sense of arrow G, Fig. 13, handgrip E2, now coupled. with shaft 51, opens the switch while: cam 55,- with the movement of shaft 511,, is returned into its original rest position where: the locking bar -2: again engages the indentation 56, engagement which will only transitorilybe lifted; when. handgrip E2 is returned into its original rest position and on its passage: contacts with its cam- 59 the locking bar shortly.

All parts are thus returned into the original rest position of Fig. 9.

The arrangement and. the. functioning of the: remote control mechanism will now be described.

Lever. i! which is? pivoted to a stationary pivot 5.9 is linked by means. of rod- Hi and pivot 73 to the armature P5 of: the electromagnet T4 for remote control. The free: end 88 of lever i? is. formed as a hook againstwhich bears the end 3-! of: a lever 82- securedv tosleeve 33. The other end 85 of lever 82' is forked. The fork 85 em braces with clearance a: crank pin 89 of a crank arm 58 which is secured to shaft 5|.

The masses of the hook. lever ll, as Fig. 14. likewise illustrates, are so distributed that the center ofgravity is: eccentric with regard to the link pivot l8 and is. lying above the same so that the moment ofgravity of the top heavy hook lever 11 pulls: the armature 15 out of the electromagnet 15- when the electromagnet is nnexcited. v

Lever 82-, 85, is so. shaped, as Figs. 9 and 1a illustrate, that its: center of graviiry is eccentric: and is lying towards? the fork side of lever 82: sothat the resulting moment. of gravity will tend to turn lever 82- and. with it sleeve 83 m asense opposite to that of arrow H, or counterclockwise; Lever 82, 35, is: secured to sleeve 83' and crank 82, 89, to shaft 51- so. that in the open position of shaft 5!, where the locking bar 52 err-- gages the indentation 56,, lever 8.5, bearing with its end: 8|v against hook 80 of lever '11-, will by means of sleeve 83 hold. cam 60. in the position shown in Fig. 15, where the. deepest point" or indentation 82 of thecam rise 93.- just contacts but does notdefiechthe. locking bar- 52. In this position of lever 82, the. upper branchv of fork 85 will be pulled, asFig. l4 likewise illustrates, by the resulting moment of gravity, to: bear. against the crankpin. 89, these end positions of hock lever L7. and. lever 82 being secured by a.

proper abutmentfor anyone-of the members; for instance, for the stroke of the armature '55, as indicatedat 94. I

Instead of the. afo'resaid distribution of the masses or shaping of lever 82 for obtaining: the desired moment, the: drawing in the sense opposite to that of arrow H, or' counterclockwise, or in addition thereto;,one" or; more springs may be provided at the members such asiaz spring QE at the lower branchiof fork 85:.

Since in the open. position. of: the switch, shaft 5!, which carries, the: movable equipment 153 of the switch, is. securely lockedv against any unintentional movement through the: locking bar 52 engaged in the. indentation 551 of cam; 55 secured to shaft 5],,nris'hockor. vibrationswhichmight impart to the switch or circuit breaker as a whole a coerced movement, may cause any movement of the movable equipment, through its inertia, relatively to the stationary part or equipment of the circuit breaker or switch. Any risk that the switch or circuit breaker might be inadvertently or unintentionally closed is thus avoided.

Intended closing of the switch, however, may be achieved simply by manipulating the handgrip in the case of manual operation as described hereinbefore, or, in the case of remote control, by excitingv the electromagnet M.

The same as the closing by hand, the closing by remote control comprises two phases. The first phase in which the shaft 5i is unlocked and the second phase in which the switch is closed by turning the shaft.

In the first phase,,electromagnet is as soon as it has been excited, by means of its armature l5, withdraws rod 16 and tilts hook lever 77 about pivot 19.

Hook 8i) deflects the fork lever 82 clockwise, in the sense of arrow H. The fork 85, before it strikes crank pin 89, moves first idly, a path a,

' wise and the cam rise 93 of cam '65 will rock the locking bar 52 and lift the bar out of engagement with the indentation 56 of cam 55, and will then hold the locking bar in inactive position, out of engagement, on the circular circumference of cam 68; Cam 55 and with it shaft 5-! are thus released for movement or actuation in the closing sense, unimpeded also by the cam mechanism operable by the manual actuating means.

In the second phase of the rocking movement of fork 85, its lower branch will strike against the crank pin 89 and thus oscillate crank 88 with shaft 5!. Cam 55 of shaft 5! will with the circular part of its circumference continue to hold the locking bar 52 disengaged and shaft 5! will move the movable equipment into the closed position of the switch or circuit breaker.

When the electromagnet is de-energized, the

hook lever H by gravity will return into the position of Fig. 14 pulling with it the armature it of the electromagnet' 74. The end SI of the fork lever "I? through its moment of gravity or pulled by spring 95: or both, in the first phase of its return movement, will, by means of sleeve 83, move cam 58 back towards the position of Fig. 15, until the upper end of cam rise 93 is opposite thelocking bar 512', this bar however still being. held inactive, out of engagement, by cam In the second phase of the return movement, when the upper branch of fork has reached crank pin 89, the fork lever, on further return movement, counterclockwise, simultaneously brings the indentation S2 of cam 69 in opposition to the'lockingbar, turns-shaft 5i thus-opens the switchor circuit breaker and with shaft 55 turns cam 55 into the initial position where the the locking; bar 52,, now opposite indentation 92- isunimpeded by cam 51! and may engage the indentation 56:0f cam' 55; thus locking again the movable equipment; inxtheppen position of the: switch or circuit breaker, against unintended movement. in the closing sense.

We claim:

contact andia. movable contact, a shaft carrying said movable contact, and actuating means for closing and opening said contacts; said device including a unidirectionally selective impeding mechanism having a movement resisting member mounted at said circuit breaker independently of said shaft, a member rigidly secured at said shaft to be movable therewith and adapted for unidirectional engagement with said resisting member thereby to take up turning moments caused on coerced movement of said circuit breaker as a whole through inertia of the movable contact and produced by, and arriving at said impeding mechanism from, movement of the movable contact, and resist any unintentional closing movement of the contacts; said impeding in chanism further including release mechanism associated with said actuating means and operable thereby for disengaging said shaft member from said resisting member and thus to release the shaft for movement by turning moments produced at the shaft by intentional actuation of the actuating means for operation of the circuit breaker in either sense, opening and closing the contacts.

2. Protecting device for circuit breakers with at least one contact pair having a stationary contact and a movable contact, a shaft carrying the movable contact and actuating means on the shaft for closing and opening the contacts by means of the shaft; said device having a resisting mechanism including a stationary member, a movable member disposed on the shaft rigidly secured thereto so as to be movable therewith, and interengaging means between both said members and operatively connected therewith and resistantly movable with relation thereto, unidirectionally responsive to angular displacement of the shaft in the closing sense thereby to interengage the stationary and movable mem-- bers and to resist angular displacements of the shaft during a first certain angle of its closing movement said stationary member including release mechanism associated with said movable member and adapted to become operative on movement of the shaft above said angle; thereby to prevent unintentional closing of the contacts on movement of the movable contact through its inertia out of the open position and caused by coerced movement of the circuit breaker a whole, but to allow intentional closing of the contacts and unimpeded opening of the same, and at the end of the opening movement to bring the stationary and the movable members again into position for interengagement.

3. Protecting device for circuit breakers with at least one contact pair having a stationary contact and a movable contact, a shaft carrying the movable contact and actuating means on the shaft for closing and opening the contacts by means of the shaft; said device having a brake mechanism with two brake members movable relatively to each other, both loosely disposed on the shaft, one being stationary the other movable relatively to the stationary brake member and the shaft; said device further including mechanism for unidirectionally interengaging the movable brake member and the shaft responsive to angular displacement of the shaft in the closing sense thus to absorb by friction the energy of such angular displacement; said device further including release mechanism associated with the shaft and adapted to become operative on movement of the shaft above a certain angle and to release the brake mechanism; thereby to 12 movement out of the open position of the mov able contact through its inertia and caused by coerced movement of the circuit breaker as a whole but to allow intentional closing of the contacts and unimpeded opening of the same, and

at the end of the opening movement to bring prevent unintentional closing of the contacts on the stationary and movable brake members again into position for interengagement.

4. Protecting device as set forth in claim 3 wherein said interengaging mechanism comprises a pawl and ratchet wheel gearing; said ratchet wheel being secured to the movable brake member; a carrier disc mounted on the shaft and secured thereto, the pawl being pivotally mounted on the carrier disc, spring means, associated with the pawl, being secured to'the carrier disc and adapted to urge the pawl at the one end thereof into engagement with the ratchet wheel, stationary control means being associated with the other end of the pawl and adapted to release the pawl on a certain angle of its rotary movement with the carrier disc and shaft, out of the open position of the contacts, for engagement with the ratchet wheel, and, on rotary movement above said angle, to lift the pawl out of engagement with the ratchet wheel.

5. Protecting device as set forth in claim 4 wherein said stationary control means includes a stationary cylindrical casing loosely disposed on the shaft and with its cylindrical wall surrounding said carrier disc, the free end of the pawl being disposed and adapted to ride on the inside surface of said cylindrical wall, the pawl on contact with the wall thereby being lifted out of engagement with the ratchet wheel, windows being provided in said wall and on the path of the pawl, the peripheral lengths of the windows being determined and disposed in relation to the uninterrupted peripheral length of the Wall from window to window so as to release the pawl for engagement with the ratchet wheel on said certain angle of the shaft angular displacement.

6. Protecting device as set forth in claim 5 wherein a sleeve is mounted on the shaft, loosely enclosing the same, the movable brake member and the ratchet wheel being loosely mounted on the sleeve and the cylindrical casing keyed thereto against rotational displacement, thereby to hold the sleeve against angular displacement.

7. Protecting device as set forth in claim 6 wherein said sleeve is axially displaceable relatively to the casing and has a flange at its one end, disposed within the casing, the movable brake member and the ratchet wheel being housed within the casing and disposed between the end wall thereof and said flange of the sleeve; an adjusting ring being disposed on the other end of the sleeve, a coil spring being disposed between the adjusting ring and the end wall of the casing outside thereof; thereby to press the movable brake member between the end wall of the casing and the flange of the sleeve and to set the frictional resistance of the brake mechanism.

8. Protecting device for circuit breakers with at least one contact pair having a stationary contact and a movable contact, a shaft carrying the movable contact and actuating means associated with the shaft for closing and opening the contacts by means of the shaft; said device including a locking mechanism having a locking member, a stationary support for carrying the looking member, a stop member mounted on and se-- cured to the shaft and associated with the locking member for engaging the same in the open position of the shaft thereby to prevent movement or the shaft in the closing sense; said device further including a release member secured to, and adapted to be actuated by, said actuating means, the release member being associated with the locking member and adapted to lift the locking member out of engagement with the stop member on movement of the actuating means in the c1osing sense; and coupling means associated with the release member, the shaft, and the actuating means and adapted, on disengagement of the locking mechanism, to couple the actuating means and the shaft for closing the contacts by actuation of the actuating means; thereby to prevent unintentional closing of the contacts out of the open position of the movable contact through its inertia, on coerced movement of the circuit breaker as a whole but to allow intentional closing and opening of the contacts, and at the end of the opening movement to bring again the locking member into engagement with the stop member.

9. Protecting device as set forth in claim 8 wherein said locking member is a bar mounted on said support, and the stop member is a cam with a stop thereon mounted on and secured to the shaft, a spring being provided at the support disposed and adapted to urge the locking bar against the stop cam.

10. Protecting device as set forth in claim 9 wherein said actuating means is provided with u a release cam loosely mounted on the shaft and adapted for cooperation with the locking bar, thereby, on actuation of the actuating means, to lift the locking bar out of engagement with the stop of the stop cam.

11. Protecting device as set forth in claim 8 wherein said actating means comprise switch- 5 Number ing means for manual operation and switching means for remote control; each separately provided with a release cam secured thereto and separately loosely mounted on the shratt; the locking member being a bar pivotally mounte on said support; said stop member being a cam with a stop thereon and mounted on and secured to the shaft, a spring being provided at said support disposed and adapted to urge the locking bar against the stop can; the release cams being adapted for cooperation with the locking bar, thereby, on actuation of any of said two switching means to lift the locking bar out of engagement with the stop of the stop cam.

12. Protecting device as set forth in claim 8 wherein said release member is rotatably mounted on the shaft and the coupling means include abutment means mounted to the shaft and cooperating abutment means at said actuating means, both disposed and arranged to provide for free motion of the actuating means relatively to the abutment of the shaft; thereby to make it possible, on closing movement of the actuating means, first to disengage the locking member from the stop member and thereon, on further movement of the actuating means, to engage by means of the abutments the actuating member with the shaft and close the contacts.

ALBERT moon. ANDRE GRAS.

eferences Cited in the file of this patent UNITED STATES PATENTS Name Date 2,438,373 Oppel Mar. 23, 194.8 

